Thank you for an interesting post!
I have a question on this:

the valence electrons are not in a position to absorb the small amount of energy contained by the photons of visible light. So, these photons entering a glass slab from one side, simply re-emerge unaltered from the other side.

Then why does glass have a refractive index of 1.5, i. e. the light slows down in the glass? If photons went through analtered, they would not slow down, right?